Tough and solvent-proof polyamide-hydrazides containing aliphatic and aromatic supramolecular segments

Tough polyamides are crucial materials useful in many fields such as water purification and automobiles. Here we present a synergistic strategy to toughen polyamides by mechanistic interplays between aliphatic and aromatic supramolecular segments. The aliphatic monomer of adipic acid dihydrazide (ADH) and the aromatic monomer of 4,4′-oxydianiline (ODA) were subjected to low-temperature solution polycondensation with terephthaloyl chloride to synthesize tough aromatic–aliphatic polyamides in one step. Tailoring the mismatched supramolecular interactions between ADH and ODA segments enabled the precise control on the crystallinity, microphase separation structure and energy dissipation ability of the polymers. By varying the ratio of ADH segments to ODA segments, we obtained the optimal aromatic–aliphatic polyamides with high strength (ultimate engineering stress, 43.3 MPa), high toughness (31.2 MJ m −3 ) and remarkable solvent resistance due to the reliable supramolecular crosslinks. This synergistic toughening strategy is potentially useful to guide the design and development of strong and tough polymeric materials.